Recently, techniques of reducing the amount of liquid wastes to be drained during processing of photographic materials have been developed because of the need to prevent water pollution and to reduce processing costs, and industrial application of some developed techniques to some processing steps has already been attempted. In particular, in the color development step, as the pollution load of the liquid waste to be drained from this step is extremely large, various methods of reducing the amount of liquid waste have been proposed. For instance, there are known methods of regenerating a used color developer by means of electric dialysis as described in JP-A-54-37731, JP-A-56-1048, JP-A-56-1049, JP-A-56-27142, JP-A-56-33644, JP-A-56-149036, and JP-B-61-10199; methods of regenerating a used color developer by the use of an active charcoal as described in JP-B-55-1571 and JP-A-58-14831; methods of regenerating a used color developer by the use of an ion-exchange membrane as described in JP-A-52-105820; and methods of regenerating a used color developer by the use of an ion-exchange resin as described in JP-A-55-144240, JP-A-57-146249 and JP-A-61-95352. (The terms "JP-A" and "JP-B" as used herein mean an "unexamined published Japanese patent application" and an "examined Japanese patent publication", respectively.)
However, in these methods, it is necessary to analyze the color developer so as to control its composition and therefore high-technology process control techniques and expensive equipment are necessary for the analysis. As a result, these methods have come into only limited use, principally in large-scale laboratories.
In addition to the above-mentioned regeneration methods, other methods of reducing the amount of the replenisher added to the color developer have been proposed, in which the composition of the replenisher added to the color developer (hereinafter referred to as a "color developer replenisher") is adjusted. One means of adjusting the composition of the replenisher in such a low-replenishment processing system involves concentrating in the replenisher the expendable components, such as the color developing agent and the preservative, so that the necessary components in the necessary amounts will be replenished in the color developer even though the amount of replenisher is reduced.
Another means of reducing the amount of replenisher involves controlling the bromide ion concentration in the replenisher. Where a silver halide color photographic material is processed with a color developer, halide ions are released from the material into the color developer. In a low-replenishment processing system, in particular, the bromide ion concentration in the color developer increases over time with the progress of the processing procedure, whereby the color development is inconveniently retarded. Therefore, to prevent this phenomenon, the bromide ion concentration in the replenisher to be used in the low-replenishment processing system is adjusted to a lower value than would be the case for a replenisher for use in a general processing system.
Recently, the demand has increased for silver halide color photographic materials, especially picture-taking ones, having a high sensitivity, a high sharpness and an excellent color reproducibility, such as ISO 400 photographic materials (Super HG-400 made by Fuji Photo Film Co., Ltd.) having a high image quality comparable to that of ISO 100 photographic materials.
A known means of improving the sharpness and color reproducibility of photographic materials is to incorporate a so-called DIR coupler into the material Recently, compounds capable of improving the capacity of such DIR couplers have been proposed in JP-A-60-185950. By incorporation of such a compound, the sharpness and color reproducibility of the resulting photographic materials may be improved. However, it has been found that the photographic properties of the materials vary with the fatigue of the color developer used. The combination of the above-mentioned compound and a so-called DIR compound has been proposed in JP-A-61-255342, and other recent JP-A applications, for example, JP-A-1-107256, JP-A-1-259359, JP-A-1-269935 and JP-A-2-28637 also illustrate the combination of the above-mentioned compound and a so-called DIR compound. However, it has been found that these photographic materials still have insufficient sharpness and color reproducibility, and cannot be processed satisfactorily by conventional continuous processing methods which are generally carried out in local laboratories. This is because, where the materials are processed by a conventional continuous method in which a color developer replenisher is added to the processing bath, the color developer is highly activated or on the contrary deactivated and, as a result, the properties of the processed photographic materials are neither stable nor constant.
Hydrolyzable DIR couplers and compounds, which may improve the sharpness and color reproducibility of photographic materials without causing fluctuation of the activity of the color developer used, have been proposed in JP-A-57-151944, JP-A-58-205150, JP-A-1-210953, JP-A-1-280755 and U.S. Pat. No. 4,782,012. Specifically, the proposed DIR couplers and DIR compounds release a group in which the development inhibitor moiety is hydrolyzed in a color developer and substantially loses its development inhibiting activity. Using such hydrolyzable DIR couplers or compounds of that type, fluctuation of the activity of the color developer used may be overcome.
However, it has been found that among the proposed DIR couplers and compounds, those which release an aryloxy ion by deactivation of the development inhibitor moiety thereof in a color developer are defective, since the released aryloxy ions are taken up in the oil drops of the coupler in the photographic material being processed, causing the coupling activity of the coupler to vary. As a result, the properties of the processed photographic material fluctuate. In particular, when the reduction in the amount of replenisher added to the color developer is large, the fluctuation of the properties of the processed photographic material is also large. It has also been found that incorporation of such DIR couplers and compounds often causes bleaching fog during processing, as well as yellow stains in the processed photographic materials after the materials are stored for a long period of time.
In the present situation, although low-replenishment processing systems provide a simple and convenient means for reducing the amount of waste liquids from the photographic process, great reductions in the amount of color developer replenisher have not been adopted in the industry because of the above-mentioned problems.